JP4091040B2 - Board inspection equipment - Google Patents

Description

  The present invention relates to an inspection performed in a manufacturing process of a printed circuit board, and more particularly to a substrate inspection apparatus for performing a predetermined inspection after extracting cream solder and solder bumps disposed on a substrate. .

Generally, in the process of manufacturing a printed circuit board, there is a process of mounting electronic components on the board. When mounting, cream solder is first printed on a predetermined electrode pattern provided on the printed circuit board. Next, the electronic component is temporarily fixed on the printed circuit board based on the viscosity of the cream solder. Thereafter, the printed circuit board is guided to a reflow furnace, and soldering is performed through a predetermined reflow process. The printing state of the cream solder is inspected in the previous stage of being guided to the reflow furnace (for example, see Patent Document 1). In this technique, cream solder provided on an electrode of a substrate made of copper foil or the like is irradiated with light from obliquely above, and is imaged with a camera through a blue filter. Further, the sensitivity region of the light imaged at this time is set to be 450 nm to 550 nm at the peak wavelength.
JP-A-5-296746

  However, in the blue wavelength region as described above, irregular reflection occurs in the region where the resist exists, and the resist region is imaged brightly. Therefore, when extracting the cream solder region, it is difficult to distinguish between the cream solder and the resist, and there is a possibility that the region extraction may be hindered.

  Further, such a problem can occur in the same manner when extracting not only cream solder but also solder bumps.

  The present invention has been made in view of the above circumstances, and provides a substrate inspection apparatus capable of realizing a more accurate inspection when performing inspection regarding cream solder or bumps provided on a substrate. Is one of the main purposes.

  In the following, each means suitable for solving the above-mentioned purpose will be described in terms of items. In addition, the effect etc. peculiar to the means to respond | correspond as needed are added.

  Means 1. An ultraviolet irradiating means capable of irradiating ultraviolet light having a peak wavelength in a range of 365 nm to 420 nm from an oblique direction with respect to the substrate provided with cream solder or bump, and provided substantially directly above the substrate. Imaging means capable of imaging the reflected light from the substrate irradiated with the above, and inspection means for performing a predetermined inspection after extracting the cream solder or bump area based on image data captured by the imaging means And a substrate inspection apparatus.

  According to the means 1, ultraviolet light having a peak wavelength in the range of 365 nm to 420 nm from the oblique direction is irradiated from the ultraviolet irradiation means to the substrate provided with cream solder or bumps. In addition, reflected light from the substrate irradiated with the ultraviolet rays is imaged by an imaging means provided almost directly above the substrate. Then, based on the image data picked up by the image pickup means, the inspection means extracts a cream solder or bump area, and then performs a predetermined inspection. Thus, since ultraviolet rays having a peak wavelength in the range of 365 nm to 420 nm from the oblique direction are irradiated, irregular reflection does not occur in the resist region as in the case of blue visible light irradiation, It is possible to avoid a situation where the resist region is imaged brightly. Therefore, when extracting the cream solder area or the bump area, the cream solder or the like and the resist can be distinguished relatively clearly. As a result, inspection accuracy can be increased.

  Mean 2. The imaging means includes an optical system for visible light, or the imaging means is configured such that an allowable confusion circle diameter in ultraviolet light is set larger than an allowable confusion circle diameter in visible light. The board inspection apparatus according to claim 1.

  According to the means 2, the imaging means further comprises an optical system for visible light, or the imaging means is set such that an allowable confusion circle diameter in ultraviolet light is larger than an allowable confusion circle diameter in visible light. Has been. Generally, when configuring the optical system of the image pickup means, a device for eliminating the influence of chromatic aberration as much as possible has been made in order to prevent bleeding. More specifically, it is possible to prevent bleeding during imaging by preparing a plurality of lenses corresponding to each wavelength. On the other hand, in the means 2, the imaging means has an optical system for visible light, or the imaging means has an allowable confusion circle diameter in ultraviolet light set larger than an allowable confusion circle diameter in visible light. Therefore, when imaging the reflected light of ultraviolet rays, so-called chromatic aberration occurs, and blurring may occur in the image due to this.

  On the other hand, in cream solder or the like, a small dent called “medium bevel” is often formed on the top surface, and when taking a clear image so as not to be affected by chromatic aberration, There is a possibility that a dent portion due to “medium bevel” is captured darkly. And it may be judged that the darkly imaged area is not an area such as cream solder, and there is a concern that the area of the cream solder or the like may be separated from the actual area. .

  On the other hand, in the means 2, by using an optical system for visible light, or by setting the permissible circle of confusion for ultraviolet rays to be larger than the permissible circle of confusion for visible light, so-called intentionally blurring occurs. I am going to let you. Therefore, even if “medium bevel” is present, the portion is not blurred and darkened, and the entire region such as cream solder becomes bright. Therefore, when extracting the area of cream solder or the like, it is possible to effectively wipe out the influence of “medium bedding”. As a result, it is possible to further improve the inspection accuracy. Note that “having an optical system for visible light” can be replaced with the phrase “having only a lens suitable for the wavelength range of visible light”.

  Means 3. Ultraviolet irradiation means capable of irradiating ultraviolet light having a peak wavelength within a range of 365 nm to 420 nm from an oblique direction with respect to the substrate provided with cream solder or bumps, and smaller than the ultraviolet irradiation means with respect to the substrate Visible light irradiating means capable of irradiating visible light having a peak wavelength in a range of 520 nm to 680 nm at an incident angle, and reflected light from the substrate which is provided almost directly above the substrate and irradiated with the ultraviolet rays And an imaging unit capable of imaging reflected light from the substrate irradiated with the visible light, and extracting the cream solder or bump region based on the image data captured by the imaging unit And an inspection means for inspecting the substrate.

  According to the means 3, the substrate is irradiated with ultraviolet rays having a peak wavelength in the range of 365 nm to 420 nm from the oblique direction from the ultraviolet irradiation means. In addition, visible light having a peak wavelength in the range of 520 nm to 680 nm is irradiated by the visible light irradiation unit at an incident angle smaller than that of the ultraviolet irradiation unit. Furthermore, the reflected light from the substrate irradiated with ultraviolet rays and the reflected light from the substrate irradiated with visible light are imaged by the imaging means provided almost directly above the substrate. Then, based on the image data picked up by the image pickup means, the inspection means extracts a cream solder or bump area, and then performs a predetermined inspection. Thus, since ultraviolet rays having a peak wavelength in the range of 365 nm to 420 nm from the oblique direction are irradiated, irregular reflection does not occur in the resist region as in the case of blue visible light irradiation, It is possible to avoid a situation where the resist region is imaged brightly. Therefore, when extracting the cream solder area or the bump area, the cream solder or the like and the resist can be distinguished relatively clearly, and the inspection accuracy can be increased. In addition, when visible light having a peak wavelength in the range of 520 nm to 680 nm is irradiated with an incident angle smaller than that of the ultraviolet irradiation means, light from the red system electrode located around the cream solder or bump is reflected. Thus, it is easier to distinguish the color portion. For this reason, since the cream solder and the peripheral portion can be clearly distinguished, the cream solder region and the bump region can be very easily extracted. As a result, it is possible to further improve the inspection accuracy.

  Means 4. The inspection means extracts the area of the cream solder or bump on the substrate based on the image data of the visible light and extracts and masks the electrode area located around the cream solder or bump. 4. The substrate inspection apparatus according to claim 3, wherein

  In order to extract a cream solder area or the like, it is desirable to wipe out the influence of the electrode area located around the cream solder area. In this regard, according to the means 4, the area of the cream solder or the bump is extracted after the electrode area located around the cream solder or the bump is extracted and masked based on the visible light image data. Therefore, the cream solder area and the like can be extracted more appropriately, and the inspection accuracy can be further improved.

  Means 5. 5. The substrate inspection apparatus according to claim 3 or 4, wherein the visible light irradiation means can irradiate orange or red light having a peak wavelength in a range of 590 nm to 680 nm.

  According to the means 5, the visible light irradiating means emits orange to red light having a peak wavelength in the range of 590 nm to 680 nm, in particular, of the visible light. Here, the electrode or the like often exhibits a red color system, and the irradiation light is orange to red light, so that the electrode or the like can be more appropriately extracted. It should be noted that “the visible light irradiation means can irradiate red light having a peak wavelength within a range of 610 nm or more and 680 nm or less”.

  Means 6. 5. The substrate inspection apparatus according to claim 3 or 4, wherein the visible light irradiation means is capable of irradiating green light having a peak wavelength within a range of 520 nm to 570 nm.

  According to the means 6, the green light having the peak wavelength in the range of 520 nm to 570 nm in the visible light is irradiated by the visible light irradiation means. Here, among green light generally classified into R (red), G (green), and B (blue), particularly when green light existing at the center (intermediate) of the wavelength range is irradiated, other wavelength ranges Compared to, it is easier to focus and less chromatic aberration (easy to fit). Therefore, there is an advantage that it is easy to extract electrodes and the like with higher accuracy.

  Means 7. The imaging means includes an optical system for visible light, or the imaging means is configured such that an allowable confusion circle diameter in ultraviolet light is set larger than an allowable confusion circle diameter in visible light. 7. The substrate inspection apparatus according to any one of means 3 to 6.

  According to the means 7, the same effect as that of the means 2 is obtained.

  Means 8. The optical system for visible light is set so that chromatic aberration is adapted to the wavelength range of visible light irradiated from the visible light irradiation means, in particular. Inspection device.

  According to the means 8, the optical system for visible light of the imaging means is set so that the chromatic aberration is adapted to the wavelength range of visible light emitted from the visible light irradiation means. Therefore, it is easy to focus on the image data obtained by imaging the electrode, and it is not necessary to consider chromatic aberration in other wavelength regions of visible light. This is also advantageous in terms of simplifying the configuration. In particular, this means has a great merit in that it is possible to properly perform cream solder region extraction and to accurately extract electrodes and the like with a “single” imaging means. In this sense, “the above-mentioned means may be a single imaging means”.

  Means 9. Means 2 wherein the permissible circle of confusion in the optical system of the imaging means is set to be larger than the diameter of the largest of the depressions formed on the top surface of the cream solder or bump. 7. The substrate inspection apparatus according to 7 or 8.

  According to the means 9, since the permissible circle of confusion in the optical system of the imaging means is set larger than the diameter of the largest recess among the recesses formed on the top surface of the cream solder or the bump, the recess is effective. The entire area such as cream solder is brightened. In other words, it is possible to eliminate the influence of “Nakabeko”. Therefore, extraction with higher accuracy is possible when extracting an area such as cream solder. The “maximum dent diameter” refers to the diameter of the cream solder provided on the substrate that is empirically (experimentally) or theoretically that the dent can have the largest diameter. Regarding the diameter, the diameter of the maximum cream solder area may be pointed out in two dimensions, and the diameter of the cream solder area may be a predetermined ratio (for example, 80% of the diameter of the maximum cream solder area). It may be pointed to.

  Means 10. 10. The substrate inspection apparatus according to claim 1, wherein the substrate has a blue color.

  When extraction of cream solder or the like is performed based on irradiation with visible light such as blue, extraction of cream solder or the like becomes very difficult if the substrate to be inspected is blue. In this regard, even if the substrate is blue as in the means 10, irradiation with “ultraviolet rays” that are not visible light having a peak wavelength within the range of 365 nm to 420 nm from the oblique direction is performed as in the above respective means. However, since cream solder or the like is extracted based on the imaging data, the cream solder or the like can be accurately extracted without being affected by the color of the substrate. Examples of the blue substrate include “halogen-free substrate”.

  Means 11. The inspection means extracts the cream solder or bump region based on the image data, and then performs at least one determination among area measurement, measurement value determination, positional deviation determination, and bridge presence / absence determination. 11. The substrate inspection apparatus according to any one of means 1 to 10, which is executable.

  According to the means 11, after the cream solder or bump region is extracted based on the image data, at least one determination among the area measurement, measurement value determination, positional deviation determination, and bridge presence / absence determination is performed. Is executed.

  Means 12. The inspection means further includes a three-dimensional measurement means for performing three-dimensional measurement by extracting the cream solder or bump area based on the image data and then measuring the height thereof, and the tertiary The means according to any one of means 1 to 11, further comprising a three-dimensional inspection unit that performs pass / fail determination on at least one of the amount and height of the cream solder or bumps based on the original measurement result. Board inspection equipment.

  According to the means 12, not only the extraction of cream solder or bump areas, but also three-dimensional measurement is performed by measuring the height, and at least one of the amount and height of the cream solder or bumps in the three-dimensional inspection section. A pass / fail judgment is executed. Therefore, measurement based on an erroneous region is difficult to be performed, and as a result, more appropriate three-dimensional measurement can be realized.

  Hereinafter, an embodiment will be described with reference to the drawings.

  FIG. 1 is a schematic configuration diagram schematically showing an inspection apparatus 1 in the present embodiment. In the present embodiment, the inspection apparatus 1 is an inspection apparatus for inspecting the printed state of the cream solder printed on the pad PD in the printed circuit board K having the circuit pattern PT and the pad PD shown in FIG. It has. More specifically, two-dimensional measurement is performed after extracting the area of the cream solder, the area is obtained, and then the height measurement is performed on the area, thereby performing three-dimensional measurement of the cream solder and performing various inspections. It is embodied as Note that a solder resist (resist) is applied and formed on the surface of the printed circuit board K in a region other than the pad PD.

  As shown in FIG. 1, the inspection apparatus 1 includes a base 2, and an X-axis moving mechanism 3 and a Y-axis moving mechanism 4 are provided on the base 2. A rail 10 is disposed on the Y-axis moving mechanism 4, and a printed board K as a board is placed on the rail 10. The printed circuit board K is moved in the X-axis direction and the Y-axis direction by operating the X-axis moving mechanism 3 and the Y-axis moving mechanism 4.

  The inspection apparatus 1 also includes a three-dimensional measurement irradiation unit 5, a CCD camera (for example, a color camera) 6 as an imaging unit, and a main control unit 7 electrically connected to the CCD camera 6. The three-dimensional measurement irradiating means 5 is configured to irradiate a predetermined light pattern obliquely from above to the surface of the printed circuit board K in the three-dimensional measurement of cream solder. The CCD camera 6 is arranged right above the printed circuit board K, and can image the portion of the printed circuit board K irradiated with the light pattern. The main control means 7 performs image processing based on the image data captured by the CCD camera 6 by a three-dimensional measurement method, and performs three-dimensional measurement (mainly height measurement and volume measurement) of the cream solder. It is like that.

  Further, in the present embodiment, as described above, prior to the three-dimensional measurement, the cream solder is extracted, two-dimensionally measured, and the inspection related to the cream solder is also performed based on the various values measured two-dimensionally. It is like that. That is, it can be said that the main control means 7 includes inspection means 8 relating to cream solder, and the inspection means 8 includes a two-dimensional inspection unit 8A and a three-dimensional inspection unit 8B (see FIG. 6). Although a detailed description is not given here, any measurement method such as a phase shift method, a light cutting method, a spatial code method, a focusing method, or the like is appropriately employed for the three-dimensional measurement in the present embodiment.

  In this embodiment, since it has the characteristics in the two-dimensional measurement and the test | inspection containing extraction regarding the cream solder implemented in the two-dimensional test | inspection part 8A, next, such extraction etc. are demonstrated.

  The inspection apparatus 1 includes means for extracting a region where cream solder is disposed. The means includes an irradiation means 11 for extracting cream solder. The cream solder extraction irradiating means 11 irradiates the printed circuit board K with predetermined light prior to the irradiation of the light pattern by the three-dimensional measurement irradiating means 5. More specifically, as shown in FIGS. 3 and 4, the solder extracting irradiation means 11 includes a pair of upper and lower ring lights 12 and 13. The upper ring light 12 is configured to perform light irradiation (= epi-illumination) at a predetermined small incident angle (closer to irradiation from an orthogonal direction), and is configured to be able to emit red light. In particular, in the present embodiment, the red light emitted from the upper ring light 12 has a peak wavelength in the range of 610 nm to 680 nm.

  The lower ring light 13 irradiates light at a larger incident angle (obliquely) than the upper ring light 12 and is configured to be able to irradiate near ultraviolet light. In particular, in the present embodiment, the ultraviolet rays irradiated from the lower ring light 13 have a peak wavelength in the range of 365 nm or more and 420 nm or less, and the wavelength region of 430 nm or more is almost zero. Thereby, irregular reflection hardly occurs in the region where the resist exists on the printed board K, and a situation where the CCD camera 6 captures a bright image of the resist region is avoided.

  Next, the CCD camera 6 will be described. In the present embodiment, a color camera is employed as the CCD camera 6, and red light and ultraviolet rays that are reflected light can be simultaneously imaged after simultaneous irradiation from the upper ring light 12 and the lower ring light 13. ing. Of course, a monochrome camera may be adopted, but in this case, irradiation from the upper ring light 12 and the lower ring light 13 is alternately switched, and the imaging timing of red light and ultraviolet light is shifted. Also, two cameras for ultraviolet imaging and visible light (red light) imaging may be used. In this case, as a camera for ultraviolet imaging, in the sense of more positively detecting ultraviolet rays, dedicated to ultraviolet rays. It is also possible to use other cameras.

  However, the CCD camera 6 of the present embodiment includes an optical system for visible light although it is designed to pick up ultraviolet rays. In general, when configuring an optical system of a camera, a device is devised to eliminate the influence of chromatic aberration as much as possible in order to prevent bleeding. More specifically, it is possible to prevent bleeding during imaging by preparing a plurality of lenses corresponding to each wavelength. On the other hand, in the present embodiment, the chromatic aberration is set to match the wavelength range of visible light (red light) emitted from the optical system for visible light, particularly the upper ring light 12. As a result, when ultraviolet rays are imaged, slight blur occurs due to so-called chromatic aberration. On the other hand, since the chromatic aberration is adapted to the wavelength range of visible light (red light), the permissible circle of confusion is set sufficiently smaller (that is, in focus) than that of ultraviolet rays.

  In this embodiment, by adopting such an optical system and intentionally causing bleeding, the influence of a small dent called “medium bevel” formed on the top surface of the cream solder is wiped away. ing. That is, in the case where there is a “medium bevel”, if a clear image is taken so as not to be affected by chromatic aberration, there is a possibility that the concave portion due to the “medium bevel” will be imaged darkly. And it may be judged that the area imaged darkly is not a cream solder area, and when calculating a cream solder area, there is a possibility that a gap with an actual area may arise. On the other hand, in the present embodiment, by causing bleeding, even if there is a “medium bevel”, the portion does not become blurred and dark, and the entire cream solder area becomes bright. Therefore, in extracting the area of cream solder (calculating the area), the effect of “medium bevel” can be eliminated.

  The optical system will be described in more detail with reference to FIG. 5. If the effective diameter of the lens 6L of the CCD camera 6 constituting the optical system is D, the focal length is f, the focal depth is α, and the allowable circle of confusion is ε, The relationship f / D = α / ε holds. Here, the optical system is set such that the allowable confusion circle diameter ε is larger than the diameter NB when the diameter of the largest “medium bevel” that can occur is NB. As a result, the influence of all “medium bedding” can be eliminated.

  As for the diameter NB of the largest “medium bedding”, here, the diameter of the solder that can be the largest diameter in terms of experience (experimental) or theoretically regarding the cream solder provided on the printed circuit board K. Point to. Regarding the diameter, the diameter of the maximum cream solder area may be pointed out in two dimensions, and the diameter of the cream solder area may be a predetermined ratio (for example, 80% of the diameter of the maximum cream solder area). It may be pointed to.

  Next, the electrical configuration of the inspection apparatus 1 centering on the main control means 7 will be described.

  As shown in FIG. 6, the CCD camera 6 is electrically connected to the main control means 7. As described above, the main control unit 7 includes the inspection unit 8 (two-dimensional inspection unit 8A and three-dimensional inspection unit 8B). At the same time, the main control means 7 is connected to a pattern data input means 17 for inputting rough information such as printed cream solder arrangement data and circuit pattern data relating to the printed circuit board K.

  The main control means 7 is connected to the irradiation control means 21. The irradiation control means 21 is connected to the three-dimensional measurement irradiation means 5 and the solder extraction irradiation means 11 (a pair of upper and lower ring lights 12 and 13), and each irradiation is based on a control signal from the main control means 7. The execution control of the means 5 and 11 (12, 13) is performed.

  The main control means 7 is also connected to the X-axis movement control means 22 and the Y-axis movement control means 23. These X-axis movement control means 22 and Y-axis movement control means 23 appropriately drive and control the X-axis movement mechanism 3 and the Y-axis movement mechanism 4 based on a control signal from the main control means 7. As a result, the printed circuit board K is appropriately moved in the X-axis direction and the Y-axis direction.

  Next, the function and effect of the inspection apparatus 1 configured as described above will be described with a focus on the contents of control performed by the main control means 7.

  First, the main control means 7 irradiates light from both ring lights 12 and 13 of the solder extraction irradiating means 11 through the irradiation control means 21 in order to perform extraction and two-dimensional measurement of the cream solder region. Then, the printed circuit board K (reflected light) irradiated with the irradiation light is imaged by the CCD camera 6. At this time, extraction of the cream solder region and two-dimensional measurement are performed based on the image data obtained by imaging.

  Here, the extraction and two-dimensional measurement of the cream solder will be described. Usually, the printed circuit board K employs a red-colored copper foil or gold plating for forming electrodes, and a blue-colored cream solder is printed thereon.

  In this case, the irradiation control means 21 irradiates the red light from the upper ring light 13 at a small incident angle via the cream solder extraction irradiating means 11 and irradiates the ultraviolet light from the lower ring light 13 from an oblique angle at a large incident angle. Let

  When ultraviolet light is irradiated from the lower ring light 12 at a large incident angle, the ultraviolet light as reflected light is irregularly reflected at the portion where the cream solder is present, and the reflected light is directed upward, and the reflected light amount to the upper (CCD camera 6) is large. On the other hand, the portion without the solder does not reflect irregularly and the amount of reflected light is small. Further, when the upper ring light 13 irradiates red light at a small incident angle, the red light as reflected light is reflected only darkly from the cream solder portion, whereas the red light from the electrode of the red line that can exist at the periphery of the cream solder. The light is reflected so that the color portion can be more easily distinguished. That is, in addition to being able to more appropriately extract the cream solder region by ultraviolet irradiation, it is possible to more positively distinguish surrounding portions (electrode portions) exhibiting a red color line by irradiating red light. In extracting the cream solder, it is desirable to wipe out the influence of the electrode region located around the cream solder. In this embodiment, the electrode region located around the cream solder is extracted and masked. Then, the area extraction of the cream solder is executed. Thereby, a cream solder area | region can be extracted more appropriately.

  Thus, in the present embodiment, prior to the three-dimensional measurement, the extraction of the cream solder as the measurement target and the two-dimensional measurement are performed. That is, the light of a predetermined wavelength range is irradiated by the ring lights 12 and 13, and the irradiated surface (reflected light) is imaged by the CCD camera 6. 7, the work of specifying (extracting) and two-dimensionally measuring the arrangement area of the cream solder is performed.

  And various inspections are performed about the cream solder mentioned above, and a quality judgment is performed. If it is determined to be defective at the stage in the two-dimensional inspection unit 8A, it is determined to be defective at the previous stage without passing through the next three-dimensional measurement. On the other hand, when it is determined that the inspection result is good, the following three-dimensional measurement is executed. In addition, although detailed description here is abbreviate | omitted about three-dimensional measurement, as above-mentioned, arbitrary measuring methods, such as a phase shift method, a light cutting method, a space code method, a focusing method, are employ | adopted suitably. As a three-dimensional measurement procedure using the phase shift method, for example, one exemplified in Japanese Patent Application Laid-Open No. 2003-279334 can be cited.

  As described in detail above, according to the present embodiment, the lower ring light 13 irradiates the printed circuit board K with ultraviolet rays having a peak wavelength in the range of 365 nm to 420 nm from the oblique direction. Further, red light having a peak wavelength in the range of 610 nm to 680 nm is irradiated by the upper ring light 12 at an incident angle smaller than that of the lower ring light 13. Further, the reflected light from the printed circuit board K irradiated with the ultraviolet light and the reflected light from the printed circuit board K irradiated with the red light are imaged by the CCD camera 6 provided almost directly above the printed circuit board K. . Then, based on each image data picked up by the CCD camera 6, the two-dimensional inspection unit 8A extracts a cream solder region, and performs a predetermined inspection thereon. Thus, since ultraviolet rays having a peak wavelength in the range of 365 nm to 420 nm from the oblique direction are irradiated, irregular reflection does not occur in the resist region as in the case of blue visible light irradiation, It is possible to avoid a situation where the resist region is imaged brightly. Therefore, when extracting the cream solder region, the cream solder and the resist can be distinguished relatively clearly, and the inspection accuracy can be increased. In addition, by irradiating the red light, the light from the red electrode located around the cream solder is reflected, and the portion of the color can be more easily distinguished. For this reason, since the cream solder and the peripheral portion can be clearly distinguished, the cream solder region and the bump region can be very easily extracted. As a result, it is possible to further improve the inspection accuracy.

  In addition, the CCD camera 6 in the present embodiment includes an optical system for visible light in spite of imaging of ultraviolet rays, and intentionally causes blurring. For this reason, the influence by the “medium bevel” formed on the top surface of the cream solder can be eliminated. In particular, the optical system is set so that the permissible circle of confusion ε is larger than the maximum diameter NB of “Nakabeko”. Thereby, the influence of all “medium bevels” can be eliminated. As a result, more accurate extraction can be performed in extracting the cream solder area (calculating the area), and an accurate inspection can be realized.

  On the other hand, the optical system for visible light is particularly set so that chromatic aberration is adapted to the wavelength range of red light emitted from the upper ring light 12. Therefore, it is easy to focus on the image data obtained by imaging the electrode, and it is not necessary to consider chromatic aberration in other wavelength regions of visible light. This is also advantageous in terms of simplifying the configuration. In particular, there is a great merit in that it is possible to properly perform cream solder region extraction and to accurately extract electrodes and the like with a single CCD camera 6.

  Although not particularly mentioned in the above example, it can be said that the configuration of the present embodiment is particularly effective when the printed circuit board K is blue. That is, when extraction of cream solder or the like is performed based on irradiation with visible light such as blue, extraction of cream solder or the like becomes very difficult if the substrate to be inspected is blue. On the other hand, in the present embodiment, even if the printed circuit board K is blue, irradiation with “ultraviolet rays” that are not visible light having a peak wavelength within the range of 365 nm to 420 nm from the oblique direction is performed, and the imaging data Therefore, the cream solder can be accurately extracted without being influenced by the color of the printed circuit board K. Examples of the blue substrate include “halogen-free substrate”.

  In addition, you may implement as follows, for example, without being limited to the content of description of embodiment mentioned above.

  (A) In the above-described embodiment, the case of inspecting the cream solder is performed before the height measurement (three-dimensional measurement) is mainly performed. However, the present invention is applicable to the case where the three-dimensional measurement is not performed. Of course. For example, the present invention can be embodied only when two-dimensional measurement such as area measurement of cream solder is performed. In addition, two-dimensional measurement may be performed for a certain part, and the three-dimensional measurement may be performed for another part. Further, for another portion, both two-dimensional measurement and three-dimensional measurement may be performed.

  (B) In the above-described embodiment, the details of the inspection contents are not particularly mentioned. For example, based on the two-dimensional measurement result, the area measurement of the cream solder to be inspected and the determination of the measurement value, the displacement determination, the cream solder It is possible to determine whether or not there is a bridge.

  (C) The image pickup means may be a line camera other than the CCD camera capable of picking up an area as in the above embodiment. Furthermore, for example, a camera that can capture images in an area or line shape, such as a CMOS camera, may be used, and the camera is not necessarily limited to a CCD camera.

  (D) In the above-described embodiment, the case of performing cream solder region extraction and two-dimensional measurement is embodied. However, the present invention may be embodied when performing solder bump region extraction and two-dimensional measurement and inspection.

  (E) The light source constituting each of the irradiating means 5, 11 and 14 may be an LED arranged in a ring shape as shown in FIG. 4, or another lamp capable of irradiating light in a predetermined wavelength range. Good. Moreover, you may employ | adopt the irradiation means which can irradiate a laser beam.

  (F) In the above embodiment, red light having a peak wavelength in the range of 610 nm or more and 680 nm or less is adopted as the visible light irradiated from the upper ringlight 12, but the peak wavelength is in the range of 590 nm or more and 680 nm or less. It is good also as irradiating orange thru | or red light which has.

  Moreover, it is good also as irradiating the green light which has a peak wavelength in the range of 520 nm or more and 570 nm or less. Here, among green light generally classified into R (red), G (green), and B (blue), particularly when green light existing at the center (intermediate) of the wavelength range is irradiated, other wavelength ranges Compared to, it is easier to focus and less chromatic aberration (easy to fit). Therefore, when green light is used as the irradiation light, there is an advantage that it is easier to extract the electrodes and the like with higher accuracy.

  Considering these, it can be said that the visible light emitted from the upper ring light 12 may be any light having a peak wavelength in the range of 520 nm to 680 nm.

  (G) In the embodiment described above, the permissible circle of confusion with respect to ultraviolet rays in the optical system of the CCD camera 6 (imaging means) is larger than the diameter of the largest recess among the recesses formed on the top surface of the cream solder (or bump). Although the diameter is set to be large, it is not always necessary to set the diameter larger than the maximum dent diameter. In that case, there is a possibility that some dents will be imaged as dark parts, but the number will be small and the area will be small compared with the case where the image is taken in a state where the focus is in exact. Therefore, in image processing to be performed later, it is possible to perform treatment by correction processing such as hole filling relatively easily.

It is a schematic perspective view which shows typically the inspection apparatus in one Embodiment. It is a schematic diagram for demonstrating the circuit pattern on the board | substrate in embodiment. It is a schematic diagram which shows arrangement | positioning structures, such as an irradiation means for cream solder extraction in embodiment. It is a cross-sectional schematic diagram which shows the arrangement structure of the irradiation means in embodiment. It is a schematic diagram for demonstrating concepts, such as an optical system in embodiment, especially an acceptable confusion circle diameter. It is a block diagram for demonstrating the electrical structure and control structure in embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Inspection apparatus, 5 ... Three-dimensional measurement irradiation means, 6 ... CCD camera as imaging means, 7 ... Main control means, 8 ... Inspection means, 8A ... Two-dimensional inspection part, 8B ... Three-dimensional inspection part, 11 ... Cream solder extraction irradiating means, 12... Upper ring light as visible light irradiating means, 13... Lower ring light as ultraviolet irradiating means.

Claims (8)

An ultraviolet irradiation means capable of irradiating ultraviolet rays having a peak wavelength in a range of 365 nm or more and 420 nm or less from an oblique direction with respect to a substrate provided with cream solder or bumps;
An imaging means provided almost directly above the substrate and capable of imaging reflected light from the substrate irradiated with the ultraviolet rays;
Based on the image data imaged by the imaging means, comprising an inspection means for performing a predetermined inspection after extracting the cream solder or bump area ,
Said imaging means, permissible circle of confusion in the ultraviolet, said one recess is formed on the top surface of the cream solder or bump of the substrate, it characterized that you have been set to be larger than the diameter of the largest recess Inspection device. An ultraviolet irradiation means capable of irradiating ultraviolet rays having a peak wavelength in a range of 365 nm or more and 420 nm or less from an oblique direction with respect to a substrate provided with cream solder or bumps;
Visible light irradiation means capable of irradiating the substrate with visible light having a peak wavelength in a range of 520 nm or more and 680 nm or less with an incident angle smaller than that of the ultraviolet irradiation means;
An imaging means provided almost directly above the substrate and capable of imaging reflected light from the substrate irradiated with the ultraviolet light and reflected light from the substrate irradiated with the visible light;
Based on the image data imaged by the imaging means, comprising an inspection means for performing a predetermined inspection after extracting the cream solder or bump area ,
Said imaging means, permissible circle of confusion in the ultraviolet, said one recess is formed on the top surface of the cream solder or bump of the substrate, it characterized that you have been set to be larger than the diameter of the largest recess Inspection device. The inspection means extracts the area of the cream solder or bump on the substrate based on the image data of the visible light and extracts and masks the electrode area located around the cream solder or bump. The substrate inspection apparatus according to claim 2 . The visible light irradiation means, the inspection device substrate according to claim 2 or 3, characterized in that it is capable of irradiating orange to red light having a peak wavelength within 680nm the range above 590 nm. The visible light irradiation means, the inspection device substrate according to claim 2 or 3, characterized in that the green light having a peak wavelength in the range of 520nm or more 570nm or less can be irradiated. The substrate inspection device substrate according to any one of claims 1 to 5, characterized in that it exhibits a blue color. The inspection means extracts the cream solder or bump region based on the image data, and then performs at least one determination among area measurement, measurement value determination, positional deviation determination, and bridge presence / absence determination. inspection device substrate according to any one of claims 1 to 6, characterized in that it is feasible. The inspection means further includes a three-dimensional measurement means for performing three-dimensional measurement by extracting the cream solder or bump area based on the image data and then measuring the height thereof, and the tertiary based on the original measurement results, according to any one of claims 1 to 7, characterized in that it comprises a three-dimensional inspection unit that performs quality determination on at least one of the amount and the height of the cream solder or bumps Board inspection equipment.

Images